package discovery import ( "fmt" "net" "strings" "time" "github.com/Sirupsen/logrus" ) var ( // Backends is a global map of discovery backends indexed by their // associated scheme. backends = make(map[string]Backend) ) // Register makes a discovery backend available by the provided scheme. // If Register is called twice with the same scheme an error is returned. func Register(scheme string, d Backend) error { if _, exists := backends[scheme]; exists { return fmt.Errorf("scheme already registered %s", scheme) } logrus.WithField("name", scheme).Debugf("Registering discovery service") backends[scheme] = d return nil } func parse(rawurl string) (string, string) { parts := strings.SplitN(rawurl, "://", 2) // nodes:port,node2:port => nodes://node1:port,node2:port if len(parts) == 1 { return "nodes", parts[0] } return parts[0], parts[1] } // ParseAdvertise parses the --cluster-advertise daemon config which accepts // : or : func ParseAdvertise(advertise string) (string, error) { var ( iface *net.Interface addrs []net.Addr err error ) addr, port, err := net.SplitHostPort(advertise) if err != nil { return "", fmt.Errorf("invalid --cluster-advertise configuration: %s: %v", advertise, err) } ip := net.ParseIP(addr) // If it is a valid ip-address, use it as is if ip != nil { return advertise, nil } // If advertise is a valid interface name, get the valid IPv4 address and use it to advertise ifaceName := addr iface, err = net.InterfaceByName(ifaceName) if err != nil { return "", fmt.Errorf("invalid cluster advertise IP address or interface name (%s) : %v", advertise, err) } addrs, err = iface.Addrs() if err != nil { return "", fmt.Errorf("unable to get advertise IP address from interface (%s) : %v", advertise, err) } if addrs == nil || len(addrs) == 0 { return "", fmt.Errorf("no available advertise IP address in interface (%s)", advertise) } addr = "" for _, a := range addrs { ip, _, err := net.ParseCIDR(a.String()) if err != nil { return "", fmt.Errorf("error deriving advertise ip-address in interface (%s) : %v", advertise, err) } if ip.To4() == nil || ip.IsLoopback() { continue } addr = ip.String() break } if addr == "" { return "", fmt.Errorf("couldnt find a valid ip-address in interface %s", advertise) } addr = net.JoinHostPort(addr, port) return addr, nil } // New returns a new Discovery given a URL, heartbeat and ttl settings. // Returns an error if the URL scheme is not supported. func New(rawurl string, heartbeat time.Duration, ttl time.Duration, clusterOpts map[string]string) (Backend, error) { scheme, uri := parse(rawurl) if backend, exists := backends[scheme]; exists { logrus.WithFields(logrus.Fields{"name": scheme, "uri": uri}).Debugf("Initializing discovery service") err := backend.Initialize(uri, heartbeat, ttl, clusterOpts) return backend, err } return nil, ErrNotSupported }